High data rate signal transmission is a concern in many computing systems. Current server systems, for example, often use a set of user-selected components that need to communicate with each other at high data rates. In a computer server system designed with a modular architecture incorporating individual printed circuit board (PCB) ‘blades’, for example, the blades, e.g., server blades and storage blades, are mounted in a common enclosure and share system components such as cooling fans, power supplies, and enclosure management. For the blades to work together and provide the desired data storage, processing, and communications, the server system needs to provide high data rate communication channels for communications among blades and external devices. Presently, blades and I/O devices in blade-type computer servers are commonly interconnected via high speed electrical connectors attached to a backplane or midplane PCB. This architecture creates signal integrity challenges since high frequency electrical signals may need to transit tens of inches of lossy copper traces, multiple PCB vias, and two or three electrical connectors before the signals reach their destinations. In addition, the backplane or midplane can block the flow of cooling air through the server enclosure, which increases the power required to cool sensitive electronic circuits. Current electrical interconnection systems also limit server design flexibility since blades typically must be inserted parallel to the axis of the connector pins, typically, in a direction from front to back.
Communication channels using optical signaling can avoid many of the problems associated with high frequency electrical signals, but guided optical signaling may require complex or cumbersome systems for reliably aligning and connecting optical cables or ribbons. For example, a typical optical fiber coupler must align the axes of fibers being coupled and bring the ends of the fibers into contact with each other. Further, systems containing circuit boards that use optical signaling generally produce or receive optical signals at an edge of the boards where an optical cable or fiber can be connected. Having optical components at the edge of a board has disadvantages in that electrical signals that may still need to run the length of the board and may be subject to signal loss and noise problems. Further, the available space at the edge of a circuit board or a server blade is limited, and fiber connectors and the optical fibers extending from the edge of the board must often compete for space with electrical sockets and cables. Accordingly, better systems and methods for economically and efficiently establishing and maintaining optical communication channels in systems such as servers are desired.